paper

Coupled-Channel , and Scattering from Lattice QCD

arXiv:1607.07093 · doi:10.1007/JHEP10(2016)011

Abstract

We present the first lattice QCD study of coupled-channel , and scattering in isospin-1/2 in three partial waves. Using distillation, we compute matrices of correlation functions with bases of operators capable of resolving both meson and meson-meson contributions to the spectrum. These correlation matrices are analysed using a variational approach to extract the finite-volume energy eigenstates. Utilising Lüscher's method and its extensions, we constrain scattering amplitudes in , and -wave as a function of energy. By analytically continuing the scattering amplitudes to complex energies, we investigate the -matrix singularities. Working at MeV, we find a pole corresponding to a near-threshold bound state with a large coupling to . We also find a deeply bound state, and evidence for a narrow resonance coupled predominantly to . Elastic scattering in the isospin- channel is studied and we find a weakly repulsive interaction in -wave.

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